User Profile Deleted

I work on a small network which is run by Win 2003 via a Belkin ADSL modem/router. My laptop runs on XP Pro (SP2). I recently logged off the network and put the laptop into suspend mode, expecting to come back shortly. Unfortunately is was a few hours before I came back, on my return, I found that my user profile had been lost, along with my outlook settings and account. I have managed to set up my profile again, and have had no further problems. Anyone got any ideas why this has happened?